Apparatus for producing continuous metal castings

ABSTRACT

A method and apparatus for the continuous casting of metal in which a strand is withdrawn from a flow through mold, spray cooled, guided by a curved roller apron through a withdrawl mechanism, and cut into billets. The spray box is replaceable from the line and the spray nozzles are protected from splashing. A flexible starting device carrying side rollers allows the use of a simplified curved roller apron which has a trackway to guide the starting device and requires the minimum number of billet guide rollers mounted in a staggered arrangement to allow the withdrawal of a flowered strand after a breakout. The inlet of the apron is spaced from the outlet of the spray box to reheat the strand shell for bending and allowing the use of a straight flow-through mold together with fixed bending rollers in the apron.

United States Patent [191 Vertesi APPARATUS FOR PRODUCING CONTINUOUS METAL CASTINGS 75 Inventor: Tibor Miklos vemsi, Whitby,

Canada [73] Assignee: Gamma Engineering Limited,

Burlington, Canada [22] Filed: Mar. 18, 1968 21 Appl. No.: 713,904

[52] US. Cl 164/274; 164/282 [51] Int. Cl. B22D 11/08 [58] Field of Search 164/82, 263, 274, 282, 164/283, 269

[56] References Cited UNITED STATES PATENTS 3,351,124 ll/l967 Hess 164/274 3,370,642 2/1968 Meier et al. 164/282 3,409,071 1l/1968 Ciochetto 164/274 3,446,270 5/1969 Michelson 164/282 3,447,591 6/1969 Foldessy 164/282 3,464,481 9/1969 Hartzell 164/282 3,495,651 2/1970 Rokop et al. 164/274 FOREIGN PATENTS OR APPLICATIONS 602,497 7/1960 Canada 164/274 403,172 6/1966 Switzerland 164/282 Primary ExaminerFrancis S. Husar Assistant ExaminerJohn E. Roethel Attorney, Agent, or Firm-Rogers, Bereskin & Parr [57] ABSTRACT A method and apparatus for the continuous casting of metal in which a strand is Withdrawn from a flow through mold, spray cooled, guided by a curved roller apron through a withdrawl mechanism, and cut into billets. The spray box is replaceable from the line and the spray nozzles are protected from splashing. A flexible starting device carrying side rollers allows the use of a simplified curved roller apron which has a trackway to guide the starting device and requires the minimum number of billet guide rollers mounted in a staggered arrangement to allow the withdrawal of a flowered strand after a breakout. The inlet of the apron is spaced from the outlet of the spray box to reheat the strand shell for bending and allowing the use of a straight flow-through mold together with fixed bending rollers in the apron.

23 Claims, 15 Drawing Figures U.S. Patent Dec. 9, 1975 Sheet 1 of 5 3,924,673

INVENTOR TIBOR n.VERTES| BYW 3M fi US. Patent Dec. 9 1975 Sheet 2 of5 3,924,673

IIIIIII: 2:: :3m@?:: 1 1 I 82a FIG. 7

INVENTOR. 70 570/5466 Tl BORHVERTESI Fl (5. 13 BY yaw, Emh, r m

US. Patent Dec. 9, 1975 Sheet3of5 3,924,673

BFW M;

INVENTOR. T! BORH-VERTESI us. Patent 1360.9,1975 Sheet4of5 3,924,673

INVENTOR. TIBOR M. VERTESI US. Patent Dec. 9, 1975 Sheet 5 of5 3,924,673

INVENTOR. TIBORIWERTESI illo APPARATUS FOR PRODUCING CONTINUOUS METAL CASTINGS in an elevated position and located above the mold is a ladle transporting the molten metal to the apparatus together with a tundish to receive the metal from the ladle and feed it continuously into the mold or a plurality of the molds.

To begin the continuous casting operation the bottom opening of the mold, from which the metal is to be continuously withdrawn, is initially plugged by a head attached to the end of a starting device moving along a guideway. The molten metal in the mold solidifies about the head which is then withdrawn from the bottom opening of the mold followed by a continuous strand of the metal which progressively solidifies as it emerges and recedes from the mold. Vibratory apparatus prevents the molten metal from adhering to the sides of the mold during its sojourn within the mold.

On emergence from the mold the metal strand has a thin skin which thickens inwardly by cooling as its distance from the mold increases. To speed up solidification of the strand it is passed through a spray box immediately adjacent the mold outlet. This spray box carries a plurality of risers each having a line of nozzles spraying cold water onto the strand emerging from the mold. However, the skin of the strand sometimes ruptures before it has been sufficiently thickened and this breakout results in molten metal adhering to the spray chamber and nozzles. When break-out occurs the spray chamber must be cleaned, resulting in a lengthy interruption in the operation of the machine.

It is an object of the present invention to provide, in a continuous metal casting apparatus, a spray chamber which is easily replaceable as a unit, allowing the chamber to be cleared of adhering metal after a break-out while another clean chamber enables the casting operation to proceed with a minimum of interruption.

When the continuous strand of metal emerges from the spray chamber, it travels along a curved roller apron which guides the strand to a withdrawal and straightening mechanism. The curved roller apron alters the direction of travel of the metal strand from vertical to horizontal, thus enabling the overall height of the continuous casting apparatus to be reduced and allowing the metal strand to be cut into horizontally disposed billets. This apparatus is known as a semi low head machine as opposed to a high head machine in which the solidification is wholly completed along a vertical axis. After a break-out occurs, a conventional roller apron, which consists of a series of opposing bending and guide roller pairs arranged to form a guideway or passage, must be dismantled and cleaned. Like the cleaning of the spray chamber this is a laborious job and results in lengthy delays in production in the affected line. Moreover, the break-out produces a flower" on the outside surface of the strand which solidifies and jams between the rollers of the apron or 2 damages the rollers as the strand continues to be pulled forward by the withdrawal mechanism. After a breakout in this area, the strand has to be cut into sections for removal.

It is another object of the present invention to pro vide, in a continuous metal casting apparatus, an improved roller apron which is simple in construction, and which will pass a flowered strand.

In a low head continuous casting apparatus the flow-through mold must have a curved longitudinal axis coextensive with the curved axis ofthe roller apron receiving the metal strand as it emerges from the mold and guiding it to the withdrawal and straightening mechanism. A curved mold is essential because mechanical bending forces cannot be applied to the strand while it is in its initial cooling stage and its outer shell or skin is thin. However, curved molds are expensive to produce.

It is a further object of the present invention to provide, in a continuous casting apparatus, a method and apparatus to allow use of a straight flow-through mold with a curved roller apron.

Starting devices presently used to initiate the casting operation include a rigid bar of metal carrying at one end a head configured to plug the mold and of sufficient length to pass through the roller apron and reach the withdrawal and straightening mechanism. The rigidity of such a starting device makes it cumbersome to guide and also to store when not in use. Proper coaction of the starting device with the roller apron precludes any significant degree of articulation of the bar which would cause it to buckle in the apron.

It is another object of the invention to provide a starting device which is flexible whereby it may be more easily handled and stored for re-use, and which carries guide rollers enabling simplification in construction of the roller apron.

After withdrawal of the strand of metal from the mold through the spray chamber, roller apron, and withdrawal and straightening mechanism, the starting device is disconnected from the metal strand. The disconnected starting device must be stored for re-use and this requires an additional structure either as an extension where the starting device is straight or as a shunt where a curved roller apron and starting device are used.

It is another object of the present invention to provide improved means for disconnecting and storing a flexible starting device whereby additional structural requirements are minimized.

Typical embodiments of theinvention are shown in the accompanying drawings in which:

FIGS. 1a, lb, 1c are views in side elevation of a continuous metal casting apparatus with a strand passing therethrough, FIG. la showing a mold, spray chamber,

curved roller apron, and a withdrawal and straightening mechanism, FIG. lb continuing to the right of FIG. la and showing an automatic torch-cutting mechanism and starting device storage means, and FIG. 10 continuing to the right of FIG. lb and showing billet receiving means and a feed mechanism for the starting device;

' FIG. 2 is a view in side elevation, partly in cross-section, of the spray chamber shown in FIG. la and including a side view of the head portion of a starting device; FIG. 3 is a top plan view of the spray chamber shown in FIG. 2;

FIG. 4 is a view in side elevation of the lower part of the roller apron shown in FIG. la;

FIG. 5 is a cross-sectional view of the roller apron taken along line 55 of FIG. 4, but showing passage of a starting device through the roller apron;

FIG. 6 is a cross-sectional view of the roller apron taken along line 6-6 of FIG. 4 but also showing passage of the starting device through the roller apron;

FIG. 7 (on the same sheet as FIGS. lb and 1c) is a cross-section al view of the cutting table and starting device storage means taken along line 77 of FIG. lb and 1c;

FIG. 8 is a view in side elevation of the automatic torch mechanism shown in FIG. 1b;

FIG. 9 is a cross-sectional view of the torch cutting mechanism taken along line 99 of FIG. 8;

FIG. 10 is an end view of the torch cutting mechanism taken along line 10-10 of FIG. 8;

FIG. 11 (on the same sheet FIG. 1a) is a schematic hydraulic flow diagram for the drive rollers of the withdrawal and straightening mechanism shown in FIG. 1a;

FIG. 12 is a front view, partly cross-section, of the starting chain taken along line 12l2 of FIG. 2 showing a releasable locking mechanism; and

FIG. 13 is a side elevation of starting device gravity disconnect and storage;

Referring first to FIG. 1a of the drawings, the casting apparatus consists of a tundish 14 which is supported by a carriage frame 15 movable along rails 16 which are mounted on and supporting structure 17. A ladle 18 containing molten metal is movable by a service crane (not shown) into a position above tundish 14 which takes molten metal poured from the ladle and in turn pours the molten metal into one or more continuous type straight flow-through molds 19 vertically positioned beneath the tundish. A spillover box 20 is placed on floor 21 and is located below tundish 14 adjacent mold 19 to receive overflow from the tundish. Mold 19 is fixed on a frame 22 which is connected to an oscillating mechanism 23.

A spray box 24 is fixed vertically on supporting mold table 22 immediately beneath mold 19 and is axially aligned with the mold. As shown more particularly in FIGS. 2 and 3 of the drawings, spray box 24 consists of a rectangular metal frame 25 having its inner walls lined by removable panels 26 of suitable material such as plywood. A spray riser or conduit 27 is fixed along the centre line of the outer side of each wall of frame 25 by brackets 28' and has a plurality of vertically arranged nozzles 29 projecting through apertures 30 in panels 26. The upper end of each riser 27 terminates in elbows 31 which in turn carries a quick disconnection coupling 32 detachably connected to flexible hose 33. A plurality of flanges 34 are fixed to opposing sides of frame 25 for attachment of spray box 24 to a suitable mounting 35 anchored on mold table 11. The bottom end of frame 25 is closed by a removable base panel 36 which is dropped into the frame 25 and rests on the flanges at the bottom of the frame. Panel 36 has a central aperture 37 to pass a starting device 38 (FIG. 2)

and a continuous strand 39 (see FIG. 1a) withdrawn from mold 19 downwardly through the spray box. As continuous metal strand 39 passes through spray box 24, it is cooled by water sprayed upon it from nozzles 29 fed under pressure through risers 27 from hoses 33. If a break-out occurs in the length of strand 39 within spray box 24 the molten metal will splash against panels 26 and collect on base panel 36. When such a breakout occurs and after the withdrawing operation is completed, spray box 24 may be removed by uncoupling hoses 33 from risers 27 and detaching flanges 34 from supports 35. A stand-by spray box 24 may then be mounted on supports 35, hoses 33 re-coupled with risers 27 and the apparatus is then available for a subsequent casting operation. The contaminated spray box is cleaned when convenient. It will be appreciated that spray chamber 24 could be of any suitable cross-section and would be adaptable to cooling a strand moving in a direction other than vertically downward.

Referring again to FIG. la of the drawings,'a roller apron 40 is located beneath spray box 24 and has a cur vilinear longitudinal axis co-extensive with the axis of the spray box 24 and mold 19 to provide a change, from vertical to horizontal, in the direction of movement of metal strand 39 emerging from the mold and the spray box. Apron 40 is divided into an upper bender section 41 and a lower guideway section 42, both sections being supported by a brace 43 pivotally mounted on a vertically adjustable base 44. Apron 42 is held against pivotal movement about base 44 by an adjustable chain hoist 45 anchored to frame 46. As shown more particularly in FIGS. 4 to 6 of the drawings, apron 40 includes a lower pair of wide flange beams 47 spaced apart in side to side relationship and an upper pair of wide flange beams 48 also spaced apart in side to side relationship. The inner flanges of the wide flange beams 47 are spaced from the inner flanges of wide flange beams 48 to form a pair of laterally spaced tracks 49 (FIG. 5). The lateral spacing d between the tracks 49 is sufficient to allow the strand 39 to pass be tween the tracks (i.e. with a track 49 on each side of the strand). I

Rollers 50 are located in staggered relationship along apron 40 as shown in FIGS. 1a and 4 of the drawings, i.e. any roller mounted on the inside curve is not directly opposite a roller similarly mounted on the outside curve of roller apron 40. (The rollers 50 are mounted between the beams 47, and between the beams 48 (FIG. 5) by any conventional means.)

It will be seen that if a break-out occurs in metal strand 39, the resultant flowering will not cause the strand to jam between rollers 50 in apron 40 since the strand, being still malleable, will snake through the rollers until the line can be shut down, thus avoiding damage to the rollers and a strain on the withdrawal mechanism as well as prevent further rupture of the strand. The staggered roller arrangement will also permit the continuation of the casting if the nature of the breakout is of the so-called healing type.

The wide flange beams 47 and 48 of roller apron 40 are joined together by centrally apertured abutment flanges 51 (FIGS. 1a and 4), the upper section of the apron comprising bender section 41 and the remaining sections constituting low er guideway 42 which carries a set of terminal guide flanges 52 at its free end. The top of the roller apron is held by any desired means, such as a screw jack 52a, which may be released to lower the roller apron employing the hoist 45. Near its bottom, apron 40 carries a pair of legs 53 engageable, when the apron is lowered, with a pair of mounts 54 fixed on a carriage 55 moveable along rails 56. By this construction apron 40 may be removed for general overhaul.

The inlet end of roller apron 40 is spaced a predetermined distance below the outlet end of spray box 24, the spray box being of a length to allow strand 39 to cool sufficiently to form an outer shell or skin thick enough to withstand bending forces without rupturing. By allowing strand 39 to travel a given distance (e.g. 2

or 3 feet) through an ambient (i.e. normal) temperature zone after it leaves spray box 24, heat from the liquid core of the strand dissipates through the thickened skin to make it malleable for bending which is effected by rollers 50 in bender section 41 of apron 40. By this means a straight vertically oriented flow-through mold 19 is able to be employed with a curved roller apron 40 forming a semi-low head continuous casting apparatus.

The term semi-low head is used because the apparatus is higher than apparatususing a curved mold (how ever, the straight mold here used is much less subject to wear than is a curved mold) but is lower than a conventional vertical casting machine, in which a vertical drop of 30 or 40 feet is provided to allow the strand to solidify completely before being bent. In the present apparatus, a 4 inch strand will typically have half solidified (i.e. it will have one inch thick walls) when it enters the inlet end of roller apron 40 and is bent.

A withdrawal and straightening mechanism 57 is located at the lower outlet end of roller apron 40 adjacent terminal guide flanges 52 of the apron, as shown in FIG. 1a of the drawings. Withdrawal mechanism 57 consists of two pairs of pinch or drive rollers 58 each driven by a separate hydraulic motor 59. Each drive roller 58 is urged towards metal strand 39 by pressure from a hydraulic cylinder and piston assembly 60 mounted on a fixed frame 61 and acting against a floating frame 62 on which each drive roller is journalled. Located between the two pairs of rollers 58 is a roller 63, adjustable vertically by means of a worm and screw arrangement 64 which acts to straighten metal strand 39 emerging from apron 40 by bearing against its bot tom. FIG. 11 shows schematically the hydraulic flow path for motor drives 59 in which a common input conduit 65 delivers hydraulic fluid from a pressure delivery means (not shown) directly and under equal pressure in parallel to all four motors and a common output conduit 66 from the drive motors recirculates the hydraulic fluid back to the pressure delivery means. Connection of each drive motor 59 in parallel with input and output lines 65 and 66 enables strand 39 to synchronize the circumferential speed of drive rollers 58 as it is drawn by these rollers through mechanism 57, thus achieving an even distribution of traction force applied to metal strand 39 and preventing flattening of the metal strand. In the conventional operation of a withdrawal mechanism, as mentioned previously, the drive rollers are driven, usually electrically, by individual power feed lines and because of this the rollers act individually. Synchronizing mechanisms are employed but these cannot adjust for slight/variations in the diameters of the drive rollers. Consequently the rollers in fact work against each other, and to achieve the required traction force a substantially increased load is impressed transversely through one effective roller onto the billet, which load often exceeds the permissable load limit, defonning the metal strand. This defeats the purpose of having a multiplicity of drive rollers to distribute the load and reduce pinch roll pressure applied by individual rollers to the strand. By providing independently driven hydraulic motors 59 connected in parallel, each drive roller 58 takes its share in withdrawing the metal strand, which allows operation with minimum pinch roll pressure, thus reducing the likelihood of strand de* formation.

FIGS. 1b, 2, 3, 5, 6, 7, 12 and 13 of the drawings show a starting device 38 comprising a series of blocks 67 connected or coupled by pairs of link plates 68. A

pin 69 (FIG. 2) pivotally connects each pair of link plates 68 to each block 67 and carries at each end a roller 70 located outside the adjacent link plate whereby the rollers are journally mounted on the starting device 38. As shown in FIG. 5 of the drawings, rollers 70 are spaced apart a distance sufficient to bridge the space d between the tracks 49 of roller apron 40, and to fit within the tracks 49.

- One end of starting device 38 carries a head 71 (see FIGS. 2 and 3) dimensioned or configured to plug the outlet opening of mold 19. The starting device blocks 67 carry a self-locking and self-releasing device shown in FIG. 12 of the drawings which consists of a compression spring 72 located in a bore 73 in blocks 67 parallel to and adjacent each pin 69. Spring 72 bears at each end against a ball 74 which is partially received or seated in a cone depression or recess 75, located in the inner face of each adjacent link plate 68, when the longitudinal axes of each block 67 and connecting link plates 68 are parallel, i.e. when that portion of chain 38 is straight. This results in a chain of limited flexibility, i.e. force is required to bend it. When a predetermined degree of force is applied to chain 38 (by tracks 49 acting on a pair of rollers 70), then balls 74 at each end of spring 72 will disengage from depressions 75 in link plates 68 associated with these particular rollers, allow ing the starting device to flex between that block 67 associated with the particular rollers and the adjacent connecting link plates. This construction imparts rigidity to starting device 38 in the area between the bottom outlet opening of mold l9 and the top end of roller apron 40, where there is no guideway to guide the starting device. A

In the roller apron 40, the starting device 38 still requires substantial guidance (even though it is of limited flexibility) so that it will not buckle. In conventional roller aprons, such guidance is achieved by providing closely spaced rollers 50. However, in roller apron 40, tracks 49 (FIG. 5) act on rollers 70 of the starting de vice to perform the guiding function. The tracks 49 do not interfere with passage of the strand 39. The combination of tracks 49 and rollers 70 on the starting device makes it possible to stagger rollers 50 and space them widely, since their only function is to guide the strand 39, and not to guide the starting device 38.

Starter head 71 of the starting device 38 is detachable from the starting device by means of inter-engaging latch members 76 (FIG. 2) formed on the end of head 71 and on the end of first block 67 of starting device 38; head 71 being engaged with adjacent pin 69 of the starting device through a slot 77 opening from the side of the head. A removable cap 78 is attached to head 71 through an axial rod 79 fixed to the cap which extends into the body of the head and is engaged by a dowel pin 80.

After emerging from withdrawal mechanism 57, metal strand 39 continues onto a cutting table 81 where it is cut into billets of suitable length. Before reaching cutting table 81, starting device 38 is automatically disengaged from the strand at its connection with head 71 and is withdrawn to a storage area, thus requiring no synchronous drive mechanism to shunt the starting device out of the path of the strand. FIG. 1b, FIG. 10, and FIG. 13 of the drawings show a drop track 82 which feeds from the output side of withdrawal mechanism 57 to a horizontal storage track 83 located below the line of travel of metal strand 39 as the strand emerges from the withdrawal mechanism onto cutting table 81. The

drop track 82 has spaced tracks 82a similar to tracks 49, to guide the rollers 70 of the starting device 38 into the drop track, and then into the storage track 83 (FIG. 7), the side tracks of which are also indicated at 82a. As shown in FIG. 7, the width of the strand 39 is less than the distance between the side tracks 82a, so the strand continues in a straight direction.

Mounted on storage track 83 close to the end is a hydraulic cylinder 84 having a reciprocating piston 85 which carries on its free end a pusher plate 86. Starting device 38 is fed into withdrawal mechanism 57 by the action of cylinder 84 and piston 85 on the end of the starting device which when stored bears, at its end remote from head 71, against pusher plate 86. The stroke of piston 84 need only be sufficient for head 71 of starting device 38 to engage that pair of drive rollers 58 of withdrawal mechanism 57 nearest drop track 82, after which rollers 58 may be driven in reverse to feed the starting device up through roller apron 40 and spray box 24 to plug the outlet end of mold 19.

An automatic torch cut-off mechanism 87 is shown in FIG. 1b and more particularly in FIGS. 8, 9 and of the drawings. Cut-off mechanism 87 consists of a push rod 88 freely slidable axially on rollers 89 (FIG. 10) joumalled in notches 90 of a series of cross-bars 91 (FIG. 8) which are supported by upstanding pairs of legs 92 mounted on cutting table 81. Push rod 88 is thus freely movable axially in a direction parallel to cutting table 81 and in the direction of a strand 39 moving on the cutting table. Push rod 88 is also rotatable about its axis. A cutting torch 93 is adjustably mounted on push rod 88 by a clamp 94 and extends downwardly towards cutting table 81. A stop 95 is also adjustably mounted on push rod 88 by a clamp 96 and is located on the rod forwardly of torch 93 in the direction of movement of metal strand 39 (to the right as seen in the drawings), extending downwardly into the path of the strand. A cam follower 97 is fixed to push rod 88 rearwardly of torch 93 and extends downwardly to engage a cam profile 98 which is fixed, parallel to rod 88, to a pair of spaced braces 99 each spanning a pair of legs 92. A weight 100 is connected to the forward end of push rod 88 by a cable 101 passing over a pulley 102 which is mounted on one of legs 92, the other end of the cable being fastened to an arm 103 fixed to the push rod. A second smaller weight 104 is fixed on cable 101 above weight 100. The profile of cam 98 consists of three sections, a first rear section 105 angled with respect to the axis of rod 88, a second intermediate section 106 parallel to the axis of rod 88, and a third forward section 107 again angled with respect to the rod axis. When torch mechanism 87 is in a position of rest, cam follower 97 bears against the rearward end of section 105 of cam 98 and torch 93 is directed laterally away from strand 39 with weight 100 resting on ground level as shown in FIG. 1b and weight 104 resting on an upper apertured support 108 fixed to one of legs 92. A shut-off valve (not shown) is connected through a conduit 109 with an oxygen supply which feeds torch 93. The shut-off valve is triggered to supply oxygen to torch 93 at the beginning of the forward stroke of rod 88 and cut off the supply at the end of that stroke. Pairs of vertical side rollers 110 are journalled on pairs of legs 92 at each side of strand 39 to restrain the strand laterally as it moves forwardly on horizontal rollers 111 which are journalled on cutting table 81.

In the automatic operation of torch cutting mechanism 87 the position of rest of push rod 88-and its appurtenances is shown in FIG. 8 of the drawings with cutting torch 93, stop and cam follower 97 assuming positions shown in solid lines in FIG. 9 which also shows metal strand 39 emerging from withdrawal mechanism 67 onto table 81 and meeting stop 95 located in its path. The force of strand 39 moving along table 81 and bearing against stop 95 will move push rod 88 forwardly on rollers 89 in the direction of arrows 1 12. Initial movement of push-rod 88 will open the oxygen supply valve to torch 93 while the torch is directed away from the strand. As push-rod 88 moves forward, the interaction of cam follower 97 bearing against section of cam profile 98 will cause the push-rod, together with torch 93 and stop 95, initially to rotate about the axis of the rod and by this rotation the torch will be brought to point to the edge of strand 39. When cam follower 97 reaches section 106 of cam profile 98 which is parallel with the longitudinal axis of push rod 88, the push rod stops its rotational movement, thus allowing torch 93 to pre-heat the edge of strand 39 while the push rod and strand continue to move forward. When cam follower 97 reaches and moves along section 107 of cam 98, push rod 88 will again rotate about its axis as well as moving forward and strand 39 will be severed to form a billet 113 of a desired length (which has been determined by presetting the distance between torch 93 and stop 95). As cam follower 97 reaches the forward end of section 107 of cam profile 98, the oxygen supply valve is automatically cut off and also stop 95 moves out of the path of strand 39 which allows weight 100 to return push rod 88 to its original position of rest. Weight 100 is brought to rest before the completion of return travel of push rod 88, and the rod is moved the remaining distance by the action of smaller weight 104 which decreases the momentum of the mechanism as it app roaches the final rearward stop. In the rearward position of rest of push rod 88, clamp 94 of torch 93 bears against a pair of supporting legs 92 and stop 95 is again located in the path of strand 39. The paths of travel and final forward positions of cam follower 97, torch 93 and stop 95 are shown by dotted arrows and lines in FIG. 9 of the drawings.

Positioned forwardlly of cutting table 81 is a discharge table 114 as shown in FIG. 10 of the drawings, the two tables forming a continuous conveying surface. A plurality of rollers 115 journally mounted on table 114 are rotated at a circumferential speed faster than the travelling speed of metal strand 39 to clear each severed billet 113 from the strand and allow movement of stop 95 back into the path of the strand. A billet stop 116 is located adjacent the end of discharge table 1 14 remote from cutting table 81 to arrest further forward movement of the billet which is then removed laterally from the discharge table to a storage area.

What I claim as my invention is:

1. In a continuous metal casting apparatus for producing a metal strand of predetermined width, an elongated articulated starting device, a plurality of guide rollers mounted on each side of the starting device at spaced intervals along substantially the entire length thereof, and a roller apron having a pair of laterally spaced tracks engageable by said guide rollers for guiding said starting member through said roller apron, the lateral spacing of said tracks being greater than said predetermined width so that said tracks do not interfere with passage of said strand through said roller apron.

2. Apparatus according to claim 1 whereinsaid roller apron includes upper and lower strand guide rollers, said strand guide rollers being mounted between said laterally spaced tracks in staggered relation and being spaced a substantial distance apart.

3. Apparatus according to claim 2 wherein said tracks are formed by two pairs of channels, one pair at each side of said roller apron, each pair having an upper channel and a lower channel spaced apart'to form a said track, said upper strand guide rollers being mounted between said upper channels and said lower strand guide rollers being mounted between said lower channels, the spacing between the channels of each assembly includes means to limit its flexibility to prevent change in the configuration of said chain assembly.

in the absence of a force applied to said chain assembly of less than a predetermined magnitude.

6. Apparatus according to claim 1 wherein said roller apron includes avertically oriented entrance, a horizontally oriented outlet,'a frame pivotable about a fixed fulcrum, and means for pivoting the apron about the fulcrum to move the apron to operative position.

7. Apparatus according to claim 1 including means for advancing said strand and said starting device out of said roller apron in a predetermined direction, said apparatus further including storage means for said starting device, said storage means including a second pair of laterally spaced tracks located in the path of movement of said starting device to receive said rollers of said starting device, said second pair of tracks being spaced apart by a distance greater than said predetermined width, said second pair of tracks being directed at an angle to said path of movement of said strand in a direction clear of said path of movement, to shunt said starting device out of the path of movement of said strand.

8. Apparatus according to claim 1 wherein said roller apron is curved and includes a vertically oriented inlet and a horizontally oriented outlet, said roller apron also including strand bending means adjacent the inlet of said roller apron, said apparatus further including a vertically oriented straight flow-through mold, and a vertically oriented cooling chamber located below and adjacent the outlet of said mold, said inlet of said roller apron being located below said cooling chamber with said strand bending means spaced a predetermined distance below the outlet of said cooling chamber, said predetermined distance being sufficient to allow said strand only partially to solidify and being sufficient for the skin of said strand to be softened by heat from the interior of said strand.

9. Apparatus according to claim 7 wherein said first mentioned tracks are oriented in a horizontal direction 10. Apparatus according to claim 9 including reversably operable drive roller means positioned adjacent said storage means for advancing said starting device into said storage means and for driving said strand, and for feeding said starting device back through said roller apron when reversed, said storage means including pusher means actuable to move the strand starting device therein into engagement with .said drive roller means.

11. Apparatus according to claim 9 wherein said roller apron is curved and includes a vertically oriented inlet and a horizontally oriented outlet, said-1 roller apron also including strand bending means adjacent the inlet of said roller apron, said apparatus further including a vertically oriented straight flow-through mold, and a vertically oriented cooling chamber located below and adjacent the outlet of said mold, said inlet of said roller apron being located below said cooling chamber with said strand bending means spaced a predetermined distance below the outlet of said cooling chamber, saidpredetermineddistance being sufficient to allow said strand only partially to solidify and being sufficient for the skin of said strand to be softened by 1 heat from the interior of said strand.

I 12. A starting. device for use in a continuous metal casting apparatus havinga flow-through mold, comprising: a plurality of elements coupled in series by lateral pins journalled therein toform an elongated articlated unit, a plurality of rollers carried by certain of said pins at spaced intervals along each side of said unit, and a head detachably coupled with the terminal element of said unit and adapted to plug the outlet of the flow-through mold.

13. A starting device as claimed in claim 12 in which the elongated articulated unit is a block chain comprising a series of blocks connected one with another through said pins by pairs of link plates.

14. A starting device according to claim 13 wherein said chain assembly includes means to limit its flexibility to prevent change in the configuration of said chain assembly in the absence of a force applied to said chain assembly of less than a predetermined magnitude.

15. In a continuous metal casting apparatus the combination comprising:

a. an elongated starting member comprising:

i. an articulated chain assembly including a plurality of elements coupled together in series one with another by transverse pins, with ii. a plurality of pairs of rollers oppositely journaled to said pins, and with iii. a head portion attached to one end of said chain assembly; and

b. a roller apron having a pair of laterally spacedapart tracks engaged by said rollers for supporting said starting bar member and for the passage of said starting member therealong.

16. In a continuous metal casting apparatus having a flexible starting device carrying rollers laterally therealong, storage means for said starting device comprising a pair of laterally spaced tracks having inlet means adapted to receive the starting device operatively moving in the casting apparatus but to pass a strand formed thereby, said tracks being positioned to receive the starting device by gravity feed, and means to feed the starting device back into operative position.

17. Apparatus as claimed in claim 16 in which the tracks are located below the line of travel of the strand and substantially parallel therewith.

18. Apparatus as claimed in claim 16 in which the inlet means is positioned adjacent a reversibly operable withdrawal mechanism moving said strand and the means to feed the starting device back into operative position comprises a movable pusher plate bearing against that end of the starting device stored in the storage means remote from the inlet means,.said pusher plate being actuable to move the stored starting device into engagement with the withdrawal mechanism.

19. In a continuous metal casting apparatus for producing a metal strand of predetermined width and thickness, the combination comprising:

a. a starting chain assembly having an elongated body formed by a plurality of elements articulatedly coupled together,

b. a roller apron having a pair of laterally spaced tracks, the lateral spacing of said tracks being greater than said predetermined width so that said tracks do not interfere with the passage of said strand through said roller apron,

c. each track being formed by opposed upper and lower track members, the spacing between opposed track members being less than said predetermined thickness,

d. and a plurality of guide members carried by said body at spaced intervals along substantially the entire length thereof, said guide members being engaged in said tracks for movement therein to guide said starting chain assembly through said roller apron.

20. Apparatus according to claim 19 wherein said body of said chain assembly includes means to limit its flexibility to prevent change in the configuration of said chain assembly in the absence of a force applied to said chain assembly of less than a predetermined magnitude.

21. Apparatus according to claim 19 and including means for advancing said starting chain assembly and said strand out of said roller apron in a predetermined direction, said apparatus further including storage means for said starting chain assembly, said storage means including a second pair of laterally spaced tracks located in the path of movement of said starting chain assembly and downstream of said means for advancing, the lateral spacing of said tracks of said second pair being greater than said predetermined width, said second pair of tracks being directed at an angle to said path of movement of said strand in a direction clear of said path of movement, to shunt said starting chain assembly out of the path of movement of said strand.

22. Apparatus according to claim 19 wherein said elements of said body are coupled together by transverse pins, said guide members being carried by certain of said pins.

23. Apparatus according to claim 19 wherein said roller apron includes upper and lower strand guide rollers, said strand guide rollers being mounted between said laterally spaced tracks in staggered relation and being spaced a substantial distance apart. 

1. In a continuous metal casting apparatus for producing a metal strand of predetermined width, an elongated articulated starting device, a plurality of guide rollers mounted on each side of the starting device at spaced intervals along substantially the entire length thereof, and a roller apron having a pair of laterally spaced tracks engageable by said guide rollers for guiding said starting member through said roller apron, the lateral spacing of said tracks being greater than said predetermined width so that said tracks do not interfere with passage of said strand through said roller apron.
 2. Apparatus according to claim 1 wherein said roller apron includes upper and lower strand guide rollers, said strand guide rollers being mounted between said laterally spaced tracks in staggered relation and being spaced a substantial distance apart.
 3. Apparatus according to claim 2 wherein said tracks are formed by two pairs of channels, one pair at each side of said roller apron, each pair having an upper channel and a lower channel spaced apart to form a said track, said upper strand guide rollers being mounted between said upper channels and said lower strand guide rollers being mounted between said lower channels, the spacing between the channels of each track being less than the thickness of said starting device, whereby said channels restrict sideways movement of said starting device.
 4. Apparatus according to claim 1 wherein said starting device comprises an articulated chain assembly having a plurality of elements coupled in series one with another by transverse pins, said transverse pins carrying pairs of said rollers one at each end thereof.
 5. Apparatus according to claim 4 wherein said chain assembly includes means to limit its flexibility to prevent change in the configuration of said chain assembly in the absence of a force applied to said chain assembly of less than a predetermined magnitude.
 6. Apparatus according to claim 1 wherein said roller apron includes a vertically oriented entrance, a horizontally oriented outlet, a frame pivotable about a fixed fulcrum, and means for pivoting the apron about the fulcrum to move the apron to operative position.
 7. Apparatus according to claim 1 including means for advancing said strand and said starting device out of said roller apron in a predetermined direction, said apparatus further includinG storage means for said starting device, said storage means including a second pair of laterally spaced tracks located in the path of movement of said starting device to receive said rollers of said starting device, said second pair of tracks being spaced apart by a distance greater than said predetermined width, said second pair of tracks being directed at an angle to said path of movement of said strand in a direction clear of said path of movement, to shunt said starting device out of the path of movement of said strand.
 8. Apparatus according to claim 1 wherein said roller apron is curved and includes a vertically oriented inlet and a horizontally oriented outlet, said roller apron also including strand bending means adjacent the inlet of said roller apron, said apparatus further including a vertically oriented straight flow-through mold, and a vertically oriented cooling chamber located below and adjacent the outlet of said mold, said inlet of said roller apron being located below said cooling chamber with said strand bending means spaced a predetermined distance below the outlet of said cooling chamber, said predetermined distance being sufficient to allow said strand only partially to solidify and being sufficient for the skin of said strand to be softened by heat from the interior of said strand.
 9. Apparatus according to claim 7 wherein said first mentioned tracks are oriented in a horizontal direction adjacent said storage track so that said strand moves in a horizontal direction, and said second pair of tracks extend downwardly from said first mentioned tracks and then horizontally below the path of movement of said strand.
 10. Apparatus according to claim 9 including reversably operable drive roller means positioned adjacent said storage means for advancing said starting device into said storage means and for driving said strand, and for feeding said starting device back through said roller apron when reversed, said storage means including pusher means actuable to move the strand starting device therein into engagement with said drive roller means.
 11. Apparatus according to claim 9 wherein said roller apron is curved and includes a vertically oriented inlet and a horizontally oriented outlet, said roller apron also including strand bending means adjacent the inlet of said roller apron, said apparatus further including a vertically oriented straight flow-through mold, and a vertically oriented cooling chamber located below and adjacent the outlet of said mold, said inlet of said roller apron being located below said cooling chamber with said strand bending means spaced a predetermined distance below the outlet of said cooling chamber, said predetermined distance being sufficient to allow said strand only partially to solidify and being sufficient for the skin of said strand to be softened by heat from the interior of said strand.
 12. A starting device for use in a continuous metal casting apparatus having a flow-through mold, comprising: a plurality of elements coupled in series by lateral pins journalled therein to form an elongated articlated unit, a plurality of rollers carried by certain of said pins at spaced intervals along each side of said unit, and a head detachably coupled with the terminal element of said unit and adapted to plug the outlet of the flow-through mold.
 13. A starting device as claimed in claim 12 in which the elongated articulated unit is a block chain comprising a series of blocks connected one with another through said pins by pairs of link plates.
 14. A starting device according to claim 13 wherein said chain assembly includes means to limit its flexibility to prevent change in the configuration of said chain assembly in the absence of a force applied to said chain assembly of less than a predetermined magnitude.
 15. In a continuous metal casting apparatus the combination comprising: a. an elongated starting member comprising: i. an articulated chain assembly including a plurality of eleMents coupled together in series one with another by transverse pins, with ii. a plurality of pairs of rollers oppositely journaled to said pins, and with iii. a head portion attached to one end of said chain assembly; and b. a roller apron having a pair of laterally spaced-apart tracks engaged by said rollers for supporting said starting bar member and for the passage of said starting member therealong.
 16. In a continuous metal casting apparatus having a flexible starting device carrying rollers laterally therealong, storage means for said starting device comprising a pair of laterally spaced tracks having inlet means adapted to receive the starting device operatively moving in the casting apparatus but to pass a strand formed thereby, said tracks being positioned to receive the starting device by gravity feed, and means to feed the starting device back into operative position.
 17. Apparatus as claimed in claim 16 in which the tracks are located below the line of travel of the strand and substantially parallel therewith.
 18. Apparatus as claimed in claim 16 in which the inlet means is positioned adjacent a reversibly operable withdrawal mechanism moving said strand and the means to feed the starting device back into operative position comprises a movable pusher plate bearing against that end of the starting device stored in the storage means remote from the inlet means, said pusher plate being actuable to move the stored starting device into engagement with the withdrawal mechanism.
 19. In a continuous metal casting apparatus for producing a metal strand of predetermined width and thickness, the combination comprising: a. a starting chain assembly having an elongated body formed by a plurality of elements articulatedly coupled together, b. a roller apron having a pair of laterally spaced tracks, the lateral spacing of said tracks being greater than said predetermined width so that said tracks do not interfere with the passage of said strand through said roller apron, c. each track being formed by opposed upper and lower track members, the spacing between opposed track members being less than said predetermined thickness, d. and a plurality of guide members carried by said body at spaced intervals along substantially the entire length thereof, said guide members being engaged in said tracks for movement therein to guide said starting chain assembly through said roller apron.
 20. Apparatus according to claim 19 wherein said body of said chain assembly includes means to limit its flexibility to prevent change in the configuration of said chain assembly in the absence of a force applied to said chain assembly of less than a predetermined magnitude.
 21. Apparatus according to claim 19 and including means for advancing said starting chain assembly and said strand out of said roller apron in a predetermined direction, said apparatus further including storage means for said starting chain assembly, said storage means including a second pair of laterally spaced tracks located in the path of movement of said starting chain assembly and downstream of said means for advancing, the lateral spacing of said tracks of said second pair being greater than said predetermined width, said second pair of tracks being directed at an angle to said path of movement of said strand in a direction clear of said path of movement, to shunt said starting chain assembly out of the path of movement of said strand.
 22. Apparatus according to claim 19 wherein said elements of said body are coupled together by transverse pins, said guide members being carried by certain of said pins.
 23. Apparatus according to claim 19 wherein said roller apron includes upper and lower strand guide rollers, said strand guide rollers being mounted between said laterally spaced tracks in staggered relation and being spaced a substantial distance apart. 